Relationship of newborn serum prolactin levels to the respiratory distress syndrome and maternal hypertension.

Prolactin concentrations were measured in mixed cord blood of 782 newborn infants and related to the occurrence of the respiratory distress syndrome (RDS) and maternal cardiovascular condition. Infants of 30 to 33 weeks' gestational age who developed RDS had significantly lower serum concentrations of prolactin than non-RDS infants within this same age range. No difference was observed between RDS and non-RDS infants at 34 to 36 weeks. Prolactin levels in infants delivered by preeclamptic women were greater than the levels in infants of normotensive women from 30 to 39 weeks' gestation. The levels were higher in the 40 to 42 weeks age group as well; however, the difference was not statistically significant. Infants of mothers with gestational hypertension also tended to have elevated serum prolactin concentrations. No differences were observed in infants of women presenting with a history of chronic hypertension. Within the RDS subgroups, serum prolactin levels were significantly greater in infants of preeclamptic women than in infants of normotensive women, being approximately equal to the levels in the non-RDS normotensive group.